1. Field of the Invention
This invention relates to a distributed data processing system having a passive communications network, several local systems, each local system including at least one central processing unit with associated stores, peripherals and processes, the coordination between said local systems being managed by systems intercommunication processors situated in a functional coordination layer of said distributed system and the communication between local systems occurring via a general communications network controlled by said communications protocols.
2. Description of the Prior Art
Technological progress in the field of integrated circuits (LSI) and their low cost has resulted in an evolution in the architecture and use of dataprocessing systems towards distributed systems. In distributed data processing systems there is a tendency towards subsystems exclusively devoted to users, others for the management of the resources of the distributed system and still others for managing communications between the various local subsystems connected to the general communications network.
Monitoring the communications between the local systems in a distributed system necessitates the creation of well defined communication protocols.
The main differences between the communications protocols of this invention and those of the prior art, e.g. "High level data link procedures", ref. ISO/TC 97/SC6, Data Communication Secretariat U.S.A. (ANSI) are given below.